Toyoda Koki Kabushiki Kaisha

Toyota Jidosha Kabushiki Kaisha

Jtekt Corporation

Toyota Jidosha Kogyo Kabushiki Kaisha

Yoshiharu Inaguma

Susumu Honaga

Mikio Suzuki

Hideya Kato

Kyosuke Haga

Keiichi Nakamura

Keiji Suzuki

Yutaka Mori

Kenichi Fukumura

Osamu Watanabe

Motoyasu Yamamori

Minoru Kawabata

Katsuhisa Mori

Kazuhiro Watanabe

Akio Numazawa

Hidetoshi Fujiwara

Hiroki Sato

Yoshinori Suzuki

Tsune Kobayashi

Kenichi Kikuchi

Harunori Shiratori

Kazuhisa Sugiyama

Tsuneo Tanaka

Kiyotaka Kato

Tsuyoshi Ikeda

Ryutaro Abe

Masato Tanabe

Takashi Imanishi

Nobuyuki Kawabata

Kazuya Ando

Masanori Natsume

Fumio Ukai

Hironori Hibino

Takuya Ohkubo

A transmission ratio variable mechanism in prior art provided on a steering column needs a spiral cable and hence, not only needs an extra space but is also accompanied by a risk of having a drawback such as the breakage of the cable or the like. A steering wheel shaftand an output shaftare supported in a housingattached to a steering column, to be rotatable on the same axis; first and second sun gearsdifferent slightly in the number of gear teeth are formed on facing end portions of the steering wheel shaft and the output shaft; first and second planetary gearsmeshing with the first and second sun gears are supported on a carrier; and a worm shaftmeshing with a worm wheelconnected rotationally to the carrier is constructed to be rotatable by a motorwhich is provided on the housing in a direction perpendicular to the rotational axis of the steering wheel shaft and the output shaft. Thus, it can be realized to eliminate any spiral cable and to obtain a transmission ratio variable steering devicewhich is space-saving.

Transmission ratio variable steering device

A compact and highly reliable motor vehicle steering device that does not require a spiral flat cable. The motor vehicle steering device includes variable gear ratio system that modifies the transmission ratio of the rotary motions between first steering shaft and second steering shaft. Variable gear ratio system comprises Strain Wave Gearing Speed Reducer that modifies the transmission ratio between first steering shaft and second steering shaft in response to the rotating speed of motor shaft. Motor shaft and second steering shaft forms a substantially concentric dual structure, drive motor is affixed, and output shaft is connected to motor shaft.

Motor vehicle steering device

In a hydraulic pump, a cam ring is provided in a cylindrical adaptor for movement in a radial direction, and a differential pressure control valve is provided to control internal pressure and load pressure at the front and back sides of a variable orifice to be introduced into action chambers and formed at the opposite sides of the cam ring for controlling a discharge amount of the pump in accordance with the rotation speed of the pump. The differential pressure control valve is operated under the internal pressure and load pressure respectively introduced into action chambers and the load of a thrust spring biasing the differential pressure control valve toward the internal pressure chamber. The load of the thrust spring is increased or decreased in accordance with an increase or a decrease of the load pressure. The increase or decrease of the load pressure is effected by a load pressure responsive piston loaded by a thrust spring and engaged with the differential pressure control valve at one end thereof in the internal pressure chamber.

Variable displacement pump

An electric power steering apparatus () includes a reduction mechanism (G) for transmitting the rotation of a rotating shaft () of a motor () to a ball screw nut () while reducing the speed of the rotation. The reduction mechanism includes a drive gear (), which is coaxially connected to the rotating shaft of the motor, and a driven gear (), which is arranged on the outer surface of the ball screw nut. Due to the reduction mechanism, the motor may be inclined relative to a rack shaft ().

Electronic control power steering device

The invention provides a compact and highly reliable motor vehicle steering device that does not require a spiral flat cable. The motor vehicle steering device includes variable gear ratio system that modifies the transmission ratio of the rotary motions between first steering shaft and second steering shaft. Variable gear ratio system comprises Strain Wave Gearing Speed Reducer that modifies the transmission ratio between first steering shaft and second steering shaft in response to the rotating speed of motor shaft. Motor shaft and second steering shaft forms a substantially concentric dual structure, drive motor is affixed, and output shaft is connected to motor shaft.

In a pump housing of a pump apparatus, a pump shaft is rotatably supported by two bearings and is connected to a pump unit. A rotary drive member is fixed to one end of the pump shaft projecting from the tip end portion of the housing. The rotary drive member includes a boss portion fixed to the one end of the pump shaft projecting from the housing, and a rim portion integral with the boss portion. The rim portion is offset from the boss portion to cover at least a portion of the tip end portion of the housing. A groove portion for receiving a drive belt is formed on the outer circumference of the rim portion. The widthwise center plane of the groove portion is located between the respective centers of the two bearings. In place of the groove portion, a tooth portion engageable with a drive gear may be formed on the outer circumference of the rim portion. Preferably, the pump unit is of a balanced vane type.

Pump apparatus having drive force input portion aligned with pump shaft bearing member

An electric power steering apparatus is composed of a wheel gear connected with a steering wheel, a worm shaft tooth-engaged with the wheel gear, and an electric motor rotatably driving the worm shaft in which a worm tooth portion of the worm shaft is formed with a compound lead. Further, the worm shaft is fixed in an axial direction by at least one locknut provided at a portion of a separate side of the electric motor. Further, one end of the worm shaft is rotatably supported through a ball bearing and is fixed by the locknut in the axial direction of the worm shaft, and the other end thereof is rotatably supported through another ball bearing or is fixed by a circlip through a disc-shaped spring in the axial direction. Furthermore, only respective outer rings of the ball bearings are further secured to a housing in which the worm shaft and the wheel gear are disposed.

Electric power steering apparatus

A power steering apparatus, including a pump, a power cylinder, a control valve and a switching valve. The switching valve is for connecting the cylinder chambers in accordance with pressure change of the operating fluid responsive to operation of the control valve in order to return the steering wheel toward a neutral position. When the rotation of the steering wheel is substantially stopped, the switching valve reacts to the pressure change in order to connect the cylinder chambers, so as that the higher hydraulic pressure of one of the cylinder chamber releases to the other. This hydraulic pressure releasing of the operating fluid returns the power piston toward the neural position, smoothly. The steering wheel also returns toward the neutral position in accordance with the return of the cylinder piston, so as that restoring force of the steering wheel is enhanced.

Power steering apparatus

A hydraulic bearing device includes a cylindrical bearing metal, a groove-like pocket, a dynamic pressure generation land, a fluid flowing space and an oil supply hole. The cylindrical bearing metal supports a rotating shaft. The pocket is formed in an inner peripheral surface of the bearing metal. The pocket defines the dynamic pressure generation land. The fluid flowing space is formed in the dynamic pressure generation land. The oil supply hole supplies fluid from a fluid pressure source to the pocket and the fluid flowing space. The dynamic pressure generation land which has been heated due to fluid friction is cooled by the fluid passing through the fluid flowing space formed in the dynamic pressure generation land. It is thus possible to inhibit thermal expansion of the hydraulic bearing device, especially the dynamic pressure generation land.

Hydraulic bearing device

A flow control device, responsive to the rotational speed of a pump and to load pressure, has a simple structure. And a housing of the flow control device for saving energy can make use of a general pump housing not for saving energy as a common housing. The flow control device of a power steering apparatus, arranged in a housing of a pump, includes a flow control valve and a load pressure responsive valve. The flow control valve includes a bypass spool with a control rod penetrating a metering orifice. The load pressure responsive valve is incorporated in a union for response to the load pressure. The control rod is located on the bypass spool for response to the rotational speed of the pump.

Flow control device of power steering apparatus

A hydraulic power steering apparatus includes a motor-driven pump which discharges pressurized working fluid at a flow rate proportional to the rotational speed. A load-pressure responsive valve is connected to a discharge passage to which the pressurized fluid is discharged from the pump. The load-pressure responsive valve bypasses the pressurized fluid to a reservoir when the control valve is in a neutral state, thereby reducing the amount of the pressurized fluid supplied to the control valve, and increases the amount of the pressurized fluid supplied to the control valve when the load pressure of the pump increases upon operation of the control valve. With this control, the energy consumed by the pump can be reduced.

A hydraulic power steering system includes a pump, a flow control valve, and a bypass control valve. The flow control valve responds to a pressure drop across a metering orifice disposed in a fluid supply passage so as to control the flow rate of operating fluid by bypassing a part of the operating fluid to a reservoir. A spring chamber of the flow control valve is connected to the supply passage through a control orifice. The bypass control valve is disposed between the spring chamber and the reservoir so as to increase the amount of bypassed fluid by controlling the pressure in the spring chamber. The bypass control valve has a control spool, a load pressure introduction port connected to the upstream side of the control orifice for leading the load pressure to a first end of the control spool and a pilot port connected to the downstream side of the control orifice for leading the pressure in the spring chamber of the flow control valve to a second end of the control spool. Moreover, a pressure receiving area of the second end of the control spool is smaller than that of the first end of the control spool. Accordingly, a spring having a small spring constant can be used in the bypass control valve, even when the control spool is controlled within a short stroke. Further, the control spool, the load pressure introduction port, and the pilot port are formed in a sleeve.

Hydraulic power steering apparatus

A power steering apparatus including an electric motor for operating a hydraulic pump which supplies pressurized fluid, a directional control valve of center-closed type operable by a steering wheel for delivering the pressurized fluid supplied by the hydraulic pump selectively to a pair of cylinder chambers of a power cylinder through a supply passage, and motor controller for controlling the electric motor. While the steering wheel is at its neutral position, the controller drives the electric motor intermittently at such a low speed that does not deteriorate the efficiency of said electric motor so much so that differential pressure between a pressure at the supply passage and a higher one of pressures in the pair of cylinder chambers is returned to a predetermined first value.

A power steering apparatus having a fluid source for discharging pressurized fluid, a power cylinder, a control valve responsive to operation of a steering wheel for supplying the power cylinder with pressurized fluid from the fluid source, and a reservoir. The control valve has a first control portion for controlling the flow of pressurized fluid from the fluid source to the reservoir, and a second control portion for controlling the flow of pressurized fluid to the power cylinder. The first control portion has two paths connecting the fluid source and the reservoir, each of the paths being formed with at least one variable orifice of a center-open type which opens when the control valve is in a neutral state. The second control portion has two supply paths communicating with the fluid source and a pair of chambers of the power cylinder, each of the supply paths being formed with a variable orifice of a center-close type which closes when the control valve is in the neutral state, and two drain paths communicating with the pair of chambers and the reservoir, each of the drain paths being formed with a variable orifice of a center-open type which opens when the control valve is in the neutral state.

A power steering apparatus having a hydraulic pump for outputting a pressurized fluid, an assist force generation mechanism hydraulically connected to the pump through a supply passage to generate an assist force in response to rotation of a steering wheel, wherein the assist force generation mechanism has a characteristic that the back pressure thereof increases when the steering wheel is rotated. The power steering apparatus further comprises a flow control valve having a spool which is moved in response to a pressure drop at a metering orifice disposed in the middle of the supply passage, so as to control the flow rate of the pressurized fluid to be constant. The spring chamber of the flow control valve is connected to a reservoir through a drain passage, and a drain valve is disposed in the drain passage for allowing the flow of pressurized fluid from the spring chamber to the reservoir when the back pressure of the assist force generation mechanism is low, and for prohibiting the flow of the pressurized fluid when the back pressure of the assist force generation mechanism increases.

Growing community of inventors

Nagoya, Japan

Yoshiharu Inaguma